There are only three possible ways to avoid a calamitous walkout. Ted Cruz can win the nomination outright before the convention. That’s very unlikely given that he’d need to win roughly 80 percent of all the remaining delegates.

Second, Trump could reveal he has a hidden reservoir of magnanimity and patriotism, and rally his faithful to the consensus nominee. Stop laughing.

Third, the delegates could pick someone sufficiently attractive that Trump followers get over their understandable bitterness and support that candidate despite Trump’s objections. Who would that be? Certainly not Mitt Romney. Maybe a reanimated Ronald Reagan. Or Batman? I have no idea.

All of these scenarios are so unlikely in part because the split in the GOP isn’t merely about a single personality. Trump represents just the most pronounced of a spiderweb of ideological and demographic fault lines that are increasingly difficult to paper over. As Joel Kotkin put it in a column for the Orange County Register, the Republican party now “consists of interest groups that so broadly dislike each other that they share little common ground.”

Put simply, and with the incessant and obtuse comparisons of Trump to Reagan notwithstanding, you cannot have a party that’s both Reaganite and Trumpish.